Etching line with integrated electrochemical regeneration for copper recovery and sludge reduction

Pollution of surface and groundwater by heavy metals, including copper, is currently a global environmental problem. Elevated concentrations of heavy metals in wastewater and soil contamination degrade the quality of water used for the supply of cities, rural settlements, and industrial facilities. The discharge and on-site storage of spent etching solutions at industrial enterprises lead to environmental pollution and require substantial costs for their neutralization both at the enterprise itself and at wastewater treatment facilities located in production areas. We have developed a technology for the recovery of heavy metals (copper) and the corresponding reduction of sludge accumulation on the premises of printed circuit board manufacturing enterprises. The proposed etching line with integrated electrochemical regeneration provides a technologically and environmentally efficient alternative to conventional printed circuit board etching systems. By redirecting rinsing waters and spent etchants into a closed-loop regeneration unit, the process eliminates wastewater discharge and substantially reduces the formation of hazardous sludge, thereby minimizing environmental impact. The line ensures a constant etching rate of printed circuit boards (substrates) within the range of 35–38 µm/min. The recovered copper can be sent for remelting and subsequent use in industrial applications. At a productivity of the printed circuit board (substrate) etching line of 14 m²/h, the regeneration unit recovers around 7 kg of copper per hour of operation (11,856 kg per year on average), while practically no waste (sludge) is generated.